Power plant comprising a toroidal combustion chamber and an axial flow gas turbine with blade cooling passages therein forming a centrifugal air compressor



Sept. 23, 1952 T sc u z 2,611,241

POWER PLANT COMPRISING A TOROIDAL COMBUSTION CHAMBER AND AN AXIAL FLOWGAS TURBINE WITH BLADE COOLING PASSAGES THEREIN FORMING A CENTRIFUGALAIR COMPRESSOR Filed March 19, 1946 2 SHEETS-SHEET 1 T/zeor/org Sc/w [zp 1952 1'. R. SCHULZ 2,611,241

POWER PLANT COMPRISING A TOROIDAL COMBUSTION CHAMBER AND AN AXIAL FLOWGAS TURBINE WITH BLADE COOLING PASSAGEB THEREIN FORMING A CENTRIFUGALAIR COMPRESSOR Filed March 19, 1946 2 SHEETS SHEET 2 ammo/whomfileocloreSCAM/Z Patented Sept. 23, 1952 UNITED STATES DEF-ICE POWER PLANTCOMPRISING A TOROIDA'L COMBUSTION CHAMBER AND AN AXIAL. FLOW' GAS.TURBINE WITH'BLADE; Coon- ING PASSAGES; THEREINY FORMING A GEN!-TBIFHGA-L AIR coMPREsSoR Theodore R; Schulz, Sylvania, Ohio, assig-norto Packard Motor Car Company, Detroit, Mich., a corporation of MichiganApp cet onMarch 19, 1946, SeriaLNa 5 5" 9. Ql'aimsi (01.60-39136) Thisinvention relates to improvementsih, gas, turbines, and has for its,principal objects; the simplification of structure. and the inerease in,efficiency of such turbines.

In the conventional gas turbine, unit,v air or other combustible gas, iscompressed; andburned with fuel in a combustion chamber, thecombuse.tion gases thus formed being supplied to. a, tur bine which inturnrotates. an impeller to effect initial compression of the, air.v Powermay be derived from the unit either by direct mechanical connection withthe, turbine shaft, or from the reaction of the gas discharged from. theunit, asv in the case of the jet propulsion engine, The instantinvention is applicable to either field, since it deals with the turbineportion item. which power can be derived, either through the torquefurnished by the turbine wheel from the exhaust gases of combustion orfrom the. reactiQZl of the gas discharged from the turbine.

It is a feature of the invention that the. same rotating part whichconstitutes. the impeller or compressor, whereby initial compression oithe air is effected, also functions as the lllll'bine wheel againstwhich the. exhaust gases are directed. In the preferred embodiment ofthe, in.-

vention, this result isv achieved by means of an impeller of thecentrifugal type, having hollow blades, the incoming air passing;through the in! terior of the blades to the diffuser section and thenceto the combustion chamber, an the. ex-.

haust combustion gases being directed: against the external surfaces ofthe blades, to rotate the impeller.

It is a further object of the invention toproe.

vide in a gas turbine, a generally toroidal cham-.

her for the collection and combustion of air or other combustible gas,the chamber being pro-. vided with annular air inletand exhaust gasoutlet openings, so that in any plane containing the generating axis of thetoroid, the air or gas partakes of generally circular motion, followingthe chamber wall. In the event the air is forced'into the chamber by acentrifugal impeller, from which the air is usually discharged in adirection not truly radial, the direction of movement of airand gaswithin the chamber will be helical.

v Thus in the application of a combined impeller and turbine wheel, ashereinabove described, to a toroidal combustion chamber, the annular airinlet of the chamber will surround the outer ends of the. hollow bladesof the impeller-turbine unit, and the combustion gases issuing from theannular outlet of the combustion chamber will be directed generallyaxially so'as. to impinge on the or gas, thereby increasing theefficiency of the unit.

Further objects and features ofthe invention will beappa-rent from thefollowing description taken in' connection with the accompanyingdrawings, in which Figure '1 is a longitudinal section: of; one formofgas turbine-embodied in the principles of the en i n;

Figure 2' is an enlargeddiagrammatie sectional View taken substantiallyonthe line 2 '2- OiFlfZ- el n Figure 3- is an end elevation at theimpeller-. turbine shown in Figure 1.

In order to facilitate an understanding of the invention, reference ismade to the embodiment selected for the purpose of illustration, andspecif c language is used.- to describe the same. 'It will, nevertheless,be appreciated that no limitation'of the scope of the invention isthereby intended, and that such further modificationsand alterations ofthe structure and function of the parts herein described arecontemplated as would be effected by those skilled in the without theexercise of invention. 3

Referring now to Figure i, it will; observed; that the illustrated unitconsists essentiallyof a stationary structure comprising agenerallytoroidal compression and combustion chamber id, and a rotatablestructure comprising a combined impeller and turbine indicated generallyat of the exhaust passage is constituted by a second which is integralwith spaced struts 28, the

latter being mounted rigidly in an axially directed generallycylindrical air inlet duct 35. The duct 30 is mounted within thetoroidal chamber by radial webs 3| which may be formed integrally withor rigidly secured to the duct and the chamber.

The structure of the impeller or compressor 1 I may vary widely, but asillustrated is of the centrifugal type, and consists essentially of ahollow hub portion 35 having a plurality of blades 36 radiatingtherefrom, the blades also being hollow and communicating directly withthe interior of the hub portion. At its forward end the hub portion isopen to afford direct communication with the rearward end of the duct30, so that air entering the forward end of the duct may move rearwardlytherein, through the hub portion of the impeller, and outwardly throughthe blades 36, being discharged from the open ends 31 of the latter.ranged in two series, one series of blades being disposed rearwardly ofthe other. Each series of blades includes a substantial number, arrangedsymmetrically about the axis of the impeller, the adjacent blades ineach series being spaced to the extent required for the flow of exhaustgases therebetween, as shown more particularly in Figure 3 of thedrawings and as hereinafter more fully described. It will beappreciated, therefore, that exhaust gas is discharged transversely ofthe annular inlet for air, defined by the hub 35 of the impeller, movingacross the air intake, the blades 36 of the impeller thus constitutingmeans for separating the air and exhaust gas. Adjacent their inner ends,proximate blades in the two series are united by a hollow ring 38integral with hollow hub 35, to strengthen the blade structure; adjacentblades in the same series may be similarly strengthened.

In describing and illustrating the blades 36 as radiating, it is notintended to imply that the; are truly radial with respect to theimpeller axis. On the contrary, as is conventional in centrifugalimpellers, it is contemplated that the blades will be so curved in theirplanes of rotation as to provide the maximum aerodynamic efiiciency. Itwill also be appreciated that the air discharging outwardly from theends 31 of the blades will not necessarily be directed radially of theimpeller, but may be given a component of movement in the direction ofrotation of the impeller by diffuser vanes 45.

Thus the discharging heated air moves through the dual annular inletopening 40 past the diffuser vanes in the chamber 10 and within thechamber in the general direction indicated by the arrows in Figure 1,but will also partake of circumferential movement about the axis of theunit, with the result that the actual movement of the air particles inthe chamber In i in a helical path.

It will be observed that the blades are arjacent portion of the wall ofchamber l0.

In order to facilitate fiow of air in this curved path within thechamber, an annular vane 43, supported by a plurality ofcircumferentially spaced struts 44 from the wall of chamber [0, isdisposed in the path of air flow, the vane having a curved configurationin transverse section corresponding generally to the curvature of thead- Fsirnilally curved diffuser vane 45 is disposed adjacent the inletopening 40 of the chamber so as to direct the helical flow of enteringair, vane 45 being supported on the chamber wall by struts 46.

To further guide and direct the flow of air, and for the additionalpurpose of separating the chamber I0 into two portions, a collectingportion and a combustion portion, an annular baflle may be provided.This baffle 50 is preferably hollow, and the interior of the baffle isdivided into two parts by an annular partition 5!. The space lyingoutside of the partition 5| is provided with insulating material 52,while the chamber 54 within partition 5| is used as a cooling chamber,through which a suitable coolant, such as air or water, may becirculated. Fins 55 extend into the cooling chamber, being formed on theinner wall of the baffle, whereby excessive heating of that wall by theproducts of combustion is avoided.

The inner wall of toroidal chamber In may be similarly treated toprevent overheating thereof, an annular chamber 60, through whichacoolant may be circulated, being suitably supported on the wall. Fins6|, forming integrally with the wall to be cooled, extend into thecooling medium in the chamber 60. V

The cooling chambers 54 and 69 are connected in order that the coolantmay be forced through both chambers from a single'source, and to thisend I provide hollow nozzle blades 65 extending between the chambers.These blades are disposed radially and are shaped in transverse sectionas shown more particularly in Figure 2 of the drawing, for the purposeof directing the exhaust gases as hereinafter mor fully described. Bythus passing coolant through the nozzle blades 65 the latter are"protected from overheating, which allows use of less expensivematerial. If air is used as coolant, chamber, 54 may communicate withthe collecting portion of chamber l0, receiving air through a number ofholes for coolant. This coolant air may also flow from'chambers 54 andthrough additional holes into combustion portion of chamber In to aidcombustion.

Extending into the combustion portion of the toroidal chamber [0 are aplurality of circumferentially spaced fuel nozzles 68, supplied withfuel from delivery lines 69, and one or more spark plugs H also extendwithin this portion of the chamber for the purpose of igniting the fuelinitially. The fuel nozzle and spark plug designs as Well as theirlocation may be of great variety and are only shown as necessary unitswithin the invention. 7

It may be polntedout that while the use of a single chamber for thecollection and burning of the gases greatly simplifies the constructionand facilitates gas flow, the practice of the invention is notnecessarily limited to such an arrangement. In any gas turbine, thecollecting chamber and the combustion chamber are necessarily in opencommunication, and may be considered, for some purposes, as a singlechamber having different portions in which different functions arecarried out, the air or other combustibl gas being collected in oneportion and being burned in an- 5. other portion... For convenience,sucha chamber isv sometimes herein designateda combustion chamber. 1

rheanozzle blades 55 are located the annular outlet of. the; chamber;1:0; through, which the combustion gases are rearwardlydischarged; itbeing. observedthatwhereas the air inlet: opening: of the chamber in:overlies the outer ends of the impeller blades 3'6, and; defines: acylindrical plane concentric with. the: axis or the unit, the outletopening of the chamber lies adjacent, the sidesv of the impeller bladesand definesna substane tially radial plane normal-to: theunitaxist Thedischarging gases are caused to: impinge on reactive surfaces formed; onthe impeller blades to provide the torque. for rotating the impeller andsupplying additional output energy, Intheillustrated form of theinvention these reactive surfacesare constituted by the: outersurfaces-of the blades 36?; the action 01". the exhaust gases on theimpeller is shown diagrammatically in Figure 2. The design of theturbine blades may be reaction, impact or some other design.

Thus the exhaust gases, on leaving the toroidal chamber iiLpa-ss betweenand are deflected by the nozzle blades 65, so as to impinge on the outersurfaces of the blades 360i the firstor forward series. Gn leaving theblades of this series, the exhaust gases pass over a second series ofnozzle blades 10, which may be formed integrally with the annular vane45, the direction of flow of the gases beingthereby again changed, so asto impinge properly against the external surfaces of the blades 36 ofthe second series. It will be appreciated that whenever desirable,additional turbine stages may be provided, only two stages beingillustrated for the purpose of simplifying the disclosure.

As hereinbefore pointed out, the air flowing through the passages withinthe blades 36 derives heat from the blades over which the exhaust gasesflow. Thus as the air enters the toroidal chamber Hi, it is not onlycompressed by the action of the impeller, but it is preheated by theexhaust gases, thermal efiiciency being. thereby improved. In order thatthis heat may not be lost, it is preferred to cover the entire outersurface of the toroidal chamber ID with an insulating sheath 18; loss ofheat to the coolant in the chamber 54 is prevented by the insulation 52in the baflie t.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

'1. In a gas turbine, the combination with a generally toroidal chamberhaving an annular air inlet, of an impeller supported for rotation onthe generating axis of the toroid, said impeller comprising hollow,radiating blades having air inlet openings adjacent the inner endsthereof, means directing air toward the inlet openings of said blades,the outer ends of said blades communicating with said chamber inlet,whereby air passing through said hollow blades is discharged into saidchamber inlet and caused to flow within said chamber in a generallyhelical path following the chamber wall, an annular baflle within saidchamber, said bafile being concentric with the generating axis of thetoroid and dividing said chamber into a collecting portion,communicating directly with said chamber inlet, and a combustion portionremote from said chamber inlet, and fuel combustion means in thecombustion portion of said chamber, the combustion portion of saidchamber being provided with an annularou-tlet directing thejgasss formedby fuel. combustion toward said impeller and against the externalsurfaces of ,said' blades, whereby said said blades, the outer ends ofsaid blades communicating withsaid chamber inlet, whereby air passingthrough said hollow bladesis discharged into said chamber inlet andcaused tdflow within said chamber in agenerally helical path about thechamber wall, an annularbaiile within said chamber, said baffle. beingconcentric, with the generating axis of' the. toroid and dividing, saidchamber "into a collecting, portion, communicating-directly with saidchamber inlet, and a combustion portion remote from said chamber imet,means for circulating a coolant. within said-baffle to cool that surface"of the bafli'e adjacent the combustion portion of said chamber,- andfuel combustion means in the combustion portion of said chamber, the'combusion portion of said chamber being provided with an annular outletdirecting the gases formed byfuel "combustion.

toward said impeller and against the external surfaces of said blades,whereby said impeller is rotated by the discharging gases.

3'. In a gas'turbine, the combination With' a generally toroidal chamberhaving an annularair inlet, an impeller for supplying air underpressureto said inlet in directions generally radial to the axis 'ofthe toroid,an annular baflie; within said chamber, said baifiebein'g'concentricwithv the generating axis of the "toroid. and dividingsaid chamber intoan outer collecting. portion, communicating directly with said inlet,and an inner combustion portion remote from said inlet and surrounded bysaid outer collecting. portion, fuel combustion, means in the combustionportion of said chamber, said chamber being provided with an'annularoutlet from which the burned gases are discharged in a directiongenerally parallel to the axis of the toroid 'andtransverse to saidinlet, and means isolating the discharging burned gases from the airsupplied to said inlet.

4. In a gas turbine, the combination with a generally toroidal chamberhaving an annular air inlet, an impeller for supplying air underpressure to said inlet in directions generally radial to the axis of thetoroid, an annular baffle within said chamber, said bafile beingconcentric with the generating axis of the toroid and dividing saidchamber into an outer collecting portion, communicating directly withsaid inlet, and an inner combustion portion remote from said inlet, fuelcombustion means in the combustion portion of said chamber, said chamberbeing provided with an annular outlet at the remote end of thecombustion portion of said chamber from which the burned gases aredischarged, and

- means for causing a coolant to circulate within the bafile and acrossthat wall of the bafile adjacent the combustion portion of the chamber.

5. In a gas turbine, the combination with a generally toroidal chamberhaving an annular air inlet, an impeller for supplying air underpressure to said inlet in directions generally radial to the axis of thetoroid, an annular bafile within said chamber, said baffle beingconcentric with the generating axis of the toroid and dividing saidchamber into an outer collecting portion,

communicating directly'with said inlet, and an inner combustion portionremote from said inlet and surrounded by said outer collecting portion,fuel combustion means in the combustion portion of said chamber, saidchamber being provided with an annular outlet at the remote end of thecombustion portion of said chamber from which the burned gases aredischarged, and means insulating that wall of the baflle adjacent thecollecting portion of the chamber.

6. In a gas turbine, the combination with a generally toroidalcombustion chamber having an annular air inlet, of an impeller supportedfor rotation on the generating axis of the toroid, said impellercomprising hollow, radiating blades having air inlet openings adjacentthe inner ends thereof, the outer ends of said blades communicating withsaid chamber inlet, whereby air passing through said hollow blades isdischarged into said chamber inlet and caused to flow within saidchamber in a generally helical path about the chamber wall, and fuelcombustion means in said chamber, said chamber being provided with anannular outlet for directing the combustion gases toward said impellerand against the external surfaces of said blades, whereby said impelleris rotated by the discharging gases.

7. In a gas turbine, the combination with a turbine wheel having hollow,radiating blades, the interiors of said blades communicating at theirinner ends with a common air inlet, a toroidal combustion chamber havingan annular air inlet surrounding the outer ends of said blades andreceiving compressed air from the interiors of said blades, said annularair inlet being formed to direct theair in a predetermined pathfollowing first the outer portion and thereafter the inner portion ofthe chamber wall, and fuel combustion means in the inner portion of saidchamber, said chamber having an annular outlet so located as todischarge combustion gases formed within said chamber in a generallyaxial direction against the external surfaces of said blades.

8. In a gas turbine, the combination with a rotating turbine wheelhaving a plurality of series of radiating blades forming a multi-stageturbine unit, said blades being formed with passages extendingtherethrough, means admitting air to the inner ends of said passages, acollecting chamber encircling the outer ends of said blades to receivecompressed airfrom said passages, means for burning fuel in saidcompressed air, and means directing the combustion gases so formedagainst said blades in a generally axial direction to rotate said wheel,said last named means including stationary nozzle blades positioned inadvance of each series of turbine blades and radiating from the axis ofthe turbine unit, said nozzle blades being formed with passagesextending therethrough, and means causing a flow of coolant through saidlast named passages.

9. In a gas turbine, the combination with a turbine wheel having hollow,radiating blades, the interiors of said blades communicating at theirinner ends with a common air inlet, a toroidal combustion chamber havingan annular air inlet surrounding the outer ends of said blades andreceiving compressed air from the interiors of said blades, fuelcombustion means in said chamber, said chamber having an annular outletso located as to discharge combustion gases formed within said chamberin a generally axial direction against the external surfaces of saidblades, and stationary annular vanes within said chamber, said vanesbeing curved in the direction of and in conformity with the curvature ofthe chamber wall, and being spaced therefrom, to cause the flow of airto follow the chamber wall.

THEODORE R. SCHULZ.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

